/*

   * Cryptographic scatter and gather helpers.

   *
   * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
   * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>

   * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>

   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License as published by the Free
   * Software Foundation; either version 2 of the License, or (at your option)
   * any later version.
   *
   */
  
  #ifndef _CRYPTO_SCATTERWALK_H
  #define _CRYPTO_SCATTERWALK_H

  #include <asm/kmap_types.h>
  #include <crypto/algapi.h>
  #include <linux/hardirq.h>
  #include <linux/highmem.h>
  #include <linux/kernel.h>

  #include <linux/mm.h>

  #include <linux/scatterlist.h>

  #include <linux/sched.h>

  static inline enum km_type crypto_kmap_type(int out)
  {
  	enum km_type type;
  
  	if (in_softirq())
  		type = out * (KM_SOFTIRQ1 - KM_SOFTIRQ0) + KM_SOFTIRQ0;
  	else
  		type = out * (KM_USER1 - KM_USER0) + KM_USER0;
  
  	return type;
  }
  
  static inline void *crypto_kmap(struct page *page, int out)
  {
  	return kmap_atomic(page, crypto_kmap_type(out));
  }
  
  static inline void crypto_kunmap(void *vaddr, int out)
  {
  	kunmap_atomic(vaddr, crypto_kmap_type(out));
  }
  
  static inline void crypto_yield(u32 flags)
  {
  	if (flags & CRYPTO_TFM_REQ_MAY_SLEEP)
  		cond_resched();
  }

  static inline void scatterwalk_sg_chain(struct scatterlist *sg1, int num,
  					struct scatterlist *sg2)
  {
  	sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0);

  	sg1[num - 1].page_link &= ~0x02;

  }
  
  static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
  {

  	if (sg_is_last(sg))
  		return NULL;

  	return (++sg)->length ? sg : (void *)sg_page(sg);
  }

  static inline void scatterwalk_crypto_chain(struct scatterlist *head,
  					    struct scatterlist *sg,
  					    int chain, int num)
  {
  	if (chain) {
  		head->length += sg->length;
  		sg = scatterwalk_sg_next(sg);
  	}
  
  	if (sg)
  		scatterwalk_sg_chain(head, num, sg);
  	else
  		sg_mark_end(head);
  }

  static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
  						struct scatter_walk *walk_out)

  {

  	return !(((sg_page(walk_in->sg) - sg_page(walk_out->sg)) << PAGE_SHIFT) +

  		 (int)(walk_in->offset - walk_out->offset));
  }
  
  static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
  {
  	unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
  	unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
  	return len_this_page > len ? len : len_this_page;

  }

  static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
  					     unsigned int nbytes)

  {

  	unsigned int len_this_page = scatterwalk_pagelen(walk);
  	return nbytes > len_this_page ? len_this_page : nbytes;

  }
  
  static inline void scatterwalk_advance(struct scatter_walk *walk,
  				       unsigned int nbytes)
  {

  	walk->offset += nbytes;

  }

  static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
  					       unsigned int alignmask)
  {
  	return !(walk->offset & alignmask);
  }

  static inline struct page *scatterwalk_page(struct scatter_walk *walk)
  {

  	return sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);

  }
  
  static inline void scatterwalk_unmap(void *vaddr, int out)
  {
  	crypto_kunmap(vaddr, out);
  }

  void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);

  void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
  			    size_t nbytes, int out);
  void *scatterwalk_map(struct scatter_walk *walk, int out);

  void scatterwalk_done(struct scatter_walk *walk, int out, int more);

  void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
  			      unsigned int start, unsigned int nbytes, int out);

  #endif  /* _CRYPTO_SCATTERWALK_H */